CONCORD — The state Republican Party believes Gov. Maggie Hassan’s campaign has accepted what it claims is an illegal contribution from the International Brotherhood of Electrical Workers Political Action Committee.

The state GOP wants the Attorney General’s Office to investigate the $25,000 contribution to Hassan’s reelection campaign on the day she filed to run for governor, June 12.

In a letter to Attorney General Joseph Foster, GOP Chairwoman Jennifer Horn says the contribution clearly exceeds the $7,000 limit in contributions to a candidate who does not agree to the state’s spending caps.

But Hassan said her campaign is following existing practice.

“We have followed past precedent and legal advice from the attorney general’s offices and the secretary of state’s office in all of our activity,” Hassan said Wednesday, “and we certainly believe our practices are consistent with past practices.”

But Republicans say the attorney general’s opinion does not permit such a contribution.

In the past, PACs have donated tens of thousands of dollars to the political parties and to PACs for Senate Republicans and Democrats and, in some instances, out-of-state PACs of presidential candidates or of those exploring a run have made contributions to gubernatorial candidates of well more than $7,000.

In 2006, the Heartland PAC of then-Iowa Gov. Tom Vilsack contributed $30,000 to NH for John Lynch before he became an official candidate that year.

But the GOP state party spokesperson said the law is clear.

“The law and the opinion of the attorney general is clear: Candidates are held to the $5,000 limit in the period before they declare their candidacy. Governor Hassan’s alarming misinterpretation of the law shows that she doesn’t believe she has to adhere to any campaign contribution limits before she officially files her candidacy,” said Lauren Zelt. “This is not only wrong, but raises questions about whether she has received even more illegal contributions during her nearly two years in office. Attorney General Foster needs to address this matter immediately to ensure that Governor Hassan’s illegal campaign contributions are not improperly influencing elections.”

The IBEW PAC is a special interest committee trying to buy influence in Concord and push elected officials, like Hassan, to support the Northern Pass transmission project, Horn noted.

“It is troubling and alarming to see that a pro-Northern Pass special interest group funded by union bosses is illegally funneling money into Governor Hassan’s reelection campaign,” said Horn.

But Hassan’s campaign said they have done nothing wrong.

“Governor Hassan appreciates the support from workers, families and businesses across New Hampshire for her efforts to create jobs and keep our economy moving in the right direction, and we are confident that all contributions are in line with past precedent under New Hampshire law and advice that campaigns and contributors have received from the Attorney General’s Office and the Secretary of State’s Office over the years,” said campaign spokesman Aaron Jacobs. “Governor Hassan continues to oppose the Northern Pass project as currently proposed and believes that the people of New Hampshire must be heard, and the project must fully investigate burying more sections of the lines.”

In her letter to Foster, Horn raises questions about Hassan’s candidate committees, noting the contribution was made to the Friends of Maggie Hassan, which became a new candidate committee on the same day.

“Clearly, Governor Hassan’s committee and the IBEW PAC have deliberately exceeded New Hampshire’s campaign contribution limits. The IBEW has also failed to follow the law by refusing to disclose its itemized receipts,” Horn wrote. “In order to ensure public confidence in state government, I ask that you investigate these important matters immediately.”

Attorney General Joseph Foster was not aware of the complaint Wednesday after the Executive Council meeting in Hanover or the specifics of a letter by previous Attorney General Michael Delaney that appears to say an exploratory committee could take uncapped contributions until the candidate actually files with the secretary of state to run for office.